Thursday, April 26, 2012

Crosswalks that work and that don’t work: Harvard St. @ Green (Brookline) versus Route 9 @ Norfolk or Dunster

Chen (Cheyenne) Chen

Crosswalks that work and that don’t work: Harvard St. @ Green (Brookline) versus Route 9 @ Dunster

Harvard St. is a two-way street without median barrier. Each direction only has one travel lane.  There are one parking lane and one bicycle lane on each side. The functionality of Harvard St. is collector road. Traffic volume is around 800 veh/h. Green Street is a one-way street shared with bicycle and one parking lane on one side. It is a local street. From the picture below we can see the area is mixed commercial and residential use together. The intended users are commuters and shoppers.

Googlemaps link:

Current Pedestrian Status
The speed limit of Harvard St. is 30 mph. The width of Harvard St. is around 48 feet. Pedestrian generally take 10 sec to cross the street.  Pedestrian volume is 500 ped/h around noon time (See the video below). The important thing is that the pedestrian volume is kind of high around this area, which forms pedestrian priority in the crosswalk. There is a pedestrian yield sign placed in the center of the road to alert driver to slow down. Thus, driver’s expectation is to slow down in this area to yield pedestrians who are walking on the crosswalk.

Moreover, there is no left turn permitted. This rule simplifies the traffic flow and reduces the conflict of pedestrian and turning vehicles.  Moreover, the number of travel lanes merges from two lanes to one lane from Beacon Street. This reduction physically forces drives to slow speed.  Based on all these factors, this crosswalk does work well for all of pedestrian, bicyclists, and motorists.


Route 9 is a two-way street with median barrier. Each direction has two travel lanes. The speed limit of Route 9 is 40 along this section. The function of Route 9 is mobility. Dunster Rd. is a two-way local street without lane line. Its function is accessibility. The traffic volume ranges from 2000 veh/h during noon time. The intended user of this crosswalk is the local residents.

Googlemaps Link:

Current Pedestrian Status
This intersection is two-way stop control in Dunster Rd.  The width of Route 9 is around 56 feet. Some vehicles are parking along two sides of this route. Here the road is straight. Driver’s expectation on speed is very high along this section. Pedestrian volume is close to zero during most time of the day and high traffic volume. Thus, under most conditions, pedestrian should yield fast vehicles. It takes around 10 seconds to cross Route 9 but it may take around 20 min for a pedestrian to find accessible gap to cross the street, which is very inconvenient for pedestrian and can cause some safety issue because of the high speed.

The two crosswalks do work for two different intended users. The pedestrian volume is high at Harvard St. @ green thus vehicles are designed to yield to pedestrian. And the pedestrian volume is close to zero at Route 9 @ Dunster . Some recommendations could be used for the crosswalk at Route 9 @ Dunster to improve pedestrian safety.

·         Install push button pedestrian signal.

·         Sharktooth yield bars can be added before the crosswalk.

·         Soft (thermoplastic) rumble strips can be added to alert motorists of an approaching “stop” or “slow down” ahead.

Pedestrian Bridge versus sidewalks on Moakley Bridge

Northern Ave, Boston

By Miao Yu (Kevin)

The Moakley Bridge and Pedestrian Bridge are both located on the east shore (Boston side) Northern Ave of the Fort Point Channel, and generally parallel to each other.
It connects two main parts of Boston, westbound is Downtown commercial area and eastbound is Seaport area, by bridging over Seaport Blvd and Northern Avenue eastbound and westbound separately.

Moakley Bridge

Moakley Bridge, which is a multiple-lanes bridge, is built across Seaport Blvd eastbound and southbound; it has two traffic lanes and one sidewalk on each side. Moakley Bridge is a key connection between eastern and western part of Boston, so the traffic flow rate is pretty high.

1)  Sidewalk
The clear sidewalk width of the Moakley Bridge is 13ft with an overall bridge width of 15ft including 1ft wide parapet walls and 1ft wide pedestrian railings on either edge. According to the standard width of a person is 2.5ft in Boston. If one meets one, it needs 5ft width. If two meet one it needs 8ft, by adding shy distance on the parapet walls edge and pedestrian railings edge, the maximum needs of two meet one is less than 11ft. So this bridge can provide very comfortable distance for two meet one.

2)   Counts of Pedestrians
The Moakley Bridge is largely used by vehicles crossing the Fort Point Channel and through the Seaport Blvd. Its users include pedestrians and bicyclists, are from multiple areas including a large number of apartments, commercial buildings, restaurants and hotels. A significant number of its users are walkers/runners, bicyclists.

Although the design of the Moakley sidewalk is pretty wide and clear for the pedestrians, the number of pedestrian crossing this bridge is much fewer than the parallel Pedestrian Bridge. By observation, there are 75 pedestrians cross through the bridge on each side during the peak 15min, 150 pax/15mins overall. 

Pedestrian Bridge

In Boston, over the Fort Point Channel, is the Pedestrian Bridge (Northern Avenue Bridge). This bridge is a swing bridge that currently is open to pedestrians only. The Northern Avenue Bridge carried road and rail traffic over the Fort Point Channel. Recently, it was blocked off and now carries only pedestrian (and bike). The bridge has nice views of the city and harbor.

From the photo above, we can see that the bridge has two pedestrian passages, but one is closed now. The other one is still works.
This bridge is considered as a scenery spot in Boston now, connecting eastern and western part of Boston, is largely used by tourists and citizens around here. On the eastbound of Northern Ave, many hotels and restaurant are located here; on the other side of this channel has a commercial area. So this bridge seems pretty popular and attractive for pedestrians.

1)  Sidewalk

The sidewalk’s width at topping and ending of the bridge is 19ft.

 The sidewalk’s width in the middle of the bridge becomes 12ft.

The width of sidewalk on the Northern Ave Bridge is 19ft at the topping and ending and 12ft in the middle. According to the standard width of a person is 2.5ft in Boston. If one meets one, it needs 5ft width. If two meet one it needs 8ft, by adding shy distance on both parapet walls edges, the maximum needs of two meet one is less than 12ft, which is the middle sidewalk width of the bridge. But it sometimes can’t supply enough space for pedestrians during the peak hour time. However, the topping and ending of the bridge can even provide three meet two, it can supply enough space for tourists taking photos and bicyclists biking through.

2) Counts of Pedestrians
Because of the good view of city and harbor, the Pedestrian Bridge is largely used by tourists for touring and taking photos and citizens for strolling and jogging. It attracts many people coming from the restaurants and hotels surrounding here and many residents living here.

Due to the long history, special design, and beautiful sea view. Most of the pedestrians choose the Pedestrian Bridge instead of Moakley Bridge, although the design of the Moakley sidewalk is modernize and clear. The number of pedestrian crossing this bridge is much higher than the parallel Moakley Bridge. Comparing with 150 pax/15min, there are 450 pedestrians cross through the bridge during the peak 15min.